1. Field of the Invention
A heat exchanger assembly and a method of fabricating a secondary heat exchanger sub-assembly in one of the tanks.
2. Description of the Prior Art
The present heat exchangers, particularly automotive radiators, often consist of a composite structure including tanks of a reinforced plastic attached to an aluminum core by crimping with gasket seals between the components. One or both of the tanks, typically the outlet tank, contains auxiliary or secondary heat exchanger sub-assemblies known as transmission oil coolers (TOC) or engine oil coolers (EOC). These heat exchanger sub-assemblies are usually fastened to the inside of the tank, e.g., by a threaded fitting extending through an opening in the tank with a nut threaded onto the fitting to sandwich a gasket seal and the tank between the nut and the fitting. Examples of such assemblies are disclosed in U.S. Pat. No. 4,665,972 to Potier; U.S. Pat. No. 5,067,561 to Joshi et al.; U.S. Pat. No. 5,113,930 to le Gauyer; U.S. Pat. No. 5,180,005 to Marsais et al.; U.S. Pat. No. 5,645,125 to Kroetsch et al.; and U.S. Pat. No. 5,937,938 to Makino et al.
Recently, more attention has been focused upon creating an all aluminum heat exchanger, e.g., an entire radiator including the tanks, to provide packaging advantages and recycling advantages with smaller tank width by eliminating the header crimp area between the core and the tanks. Whenever possible it is desirable to braze the components together rather than relying upon a mechanically held sealing connection between the components.